For better or worse, the only unabridged English translation of the Brahmanda Purana is the one by G.V. Tagare, published by Motilal Banarsidass. But what you linked to is just Volume 1 of Tagare's translation. In my question here, I gave links to all five volumes:
Here is the table of contents and index for the translation.
The online proofread version of the Brahmanda-Purana and the Lalitopakhyana also includes an interwoven Puranic glossary.
Note that volumes 1, 2, and 5 were taken from the Digital Library of India (DLI), downloaded as PDF's and then uploaded to Google Drive; if you're interested you can see my answer here for details on how to download books from DLI in PDF format. Also the link for Volume 3 is on DSpace, the digital repository for the West Bengal Public Library Network. Unfortunately the West Bengal Public Library website is down at the moment, but hopefully it will be back soon.
By the way, if you don't like Tagare's translation, you can read this extremely abbreviated translation of the Brahmanda Purana (and the other 17 Mahapuranas).